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I need to interface between an older system that uses an RS232 port for reading/writing to a tape and a more modern computer that can manipulate the data and send it back. Is there a software+hardware combo to do this?

I work at a place that uses a ~20 years old scale (Hobart SP1500) that can interface via an "RS232 Tape Recorder." I want to see if I can load and store data via a more modern computer, probably my Raspberry Pi. We have to load a lot of data onto it and I would much rather write a quick program to gather the data and write it back to the scale's internal memory.

-Sorry if this is the wrong place to ask. I first looked through google searches and RPi communities.

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    Do you mean an RS232 data logger? Old data loggers recorded on cassette tapes. Any computer with an RS232 interface should do the trick, and you can get RS232 shields (hats) for Raspberry Pis. Your main problem is going to be understanding the data stream from the scale and any commands that it expects. – Mick Mar 24 '17 at 5:32
  • @Mick Thanks for understanding what I meant, and now I'll know that terminology! As for the data stream, I hope that'll be fine as I'm really good with identifying bits. – Zeda Mar 24 '17 at 12:40
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    It looks like the Hobart cassette and diskette units control the scale, and not the other way around. Anyway, the Supervisor Manual is available online, and it seems to describe the interface in great detail. – Mick Mar 24 '17 at 12:45
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I think your best bet is an RS232-USB interface (NB I'm nor recommending the particular one linked, it was just the first one that came up in my search). Plug it in to your R-Pi's USB port and it should appear as a device in /dev. You should be able to then read and write to it like a file (well, you might not be able to write to it if your scale is only set up to send data).

If you haven't had any experience of RS232, you might find it a bit tricky to get set up. You have to configure the RS232 for speed , parity and stop bits. The Hobart manuals will probably tell you what you should set yours to.

This stackoverlfow answer goes into more detail about talking to RS232 ports on Linux and is therefore relevant to the R-Pi.

https://stackoverflow.com/a/20240650/169346

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  • Thank you, I think this is exactly the answer I was looking for! Yes, the manual did go into detail about those settings for cassette and disc. – Zeda Mar 24 '17 at 12:34
  • Could you toss the main parts of the linked document into your answer? Stack exchange likes to have the actual data available if the linked source document ever goes away. That will also increase the rep you get from your answer over time. – Rowan Hawkins Mar 24 '17 at 18:32
  • @RowanHawkins The problem is that it is just an example. It was the first link that came up when I typed "RS232 USB interface" into Google. There are many such RS232 to USB interfaces available on the market because RS232 was one of the first interfaces to be ditched by PC manufacturers when USB first came along. – JeremyP Mar 27 '17 at 9:08
  • Sorry I thought the link was for the Hobart tape drive which would be much harder to locate. I'm well aware of legacy rs232/422/485 access limitations on modern hardware. Infact, because some hardware doesn't play well with the usb/rs232 conversion because its looking for full TTL voltage. It is possible to purchase pcie boards with dual serial port interfaces. – Rowan Hawkins Mar 27 '17 at 21:42
  • IF the tape drive to be emulated followed normal serial protocol instead of bit banging things. – rackandboneman Apr 7 '17 at 11:24

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